Your father's recent death is a sad occasion. Please accept my condolences.
you need a quality estate attorney and quickly.
anyone in possession of a Will is required to deposit it with the Probate Court [or which ever one serves that purpose in your state after the person dies. The Court will then sort out which is the most recent Will and appoint the person named in it as Executor [or whatever your state calls that office].
ALL assets of the deceased are then turned over to that Executor, who then pays the bills in order specified by state law, makes the bequests in the Will, pays the estate taxes [if any], and ends up dividing the net estate to the residual beneficiaries as specified in the will.
The Executor is responsible to the Court to do all of these things in a fair and honest manner and can be sued for any lapse in that.
***
Among other things, you may wish to discuss with your attorney the following:
1. is the recent marriage valid at all? A man has to be of sound mind in order to legally marry. If your late father was in the last stages of some serious illness [as seems likely], he may have been on so many painkillers or don't worry meds that he was not of sound mind at all.
2. a will can not be amended after the testator [deceased person] has died. If the new wife wishes to claim that he promised her xyz that aren't in the Will as it is currently written, then she has to do that to the Probate Court and produce witnesses to those claims -- which would make it almost impossible for her to be the Executor as well. [this might actually be good -- she won't have access to the assets.]
GL